(1) Field of the Invention
The present invention relates to a method for manufacturing a printed circuit board, a method for manufacturing a printed circuit board assembly sheet, a printed circuit board, and printed circuit board assembly sheet.
(2) Description of Related Art
Actuators are used in drives such as hard disk drives. Such an actuator includes an arm provided rotatably around a rotation shaft, and a suspension board with a circuit for a magnetic head that is attached to the arm. The suspension board with a circuit is a printed circuit board for positioning the magnetic head at a desired track of a magnetic disk.
In processes for manufacturing such a suspension board with a circuit, a plurality of assembly sheets each including suspension boards with circuits (hereinafter abbreviated as assembly sheets) are formed on a support substrate made of a metal. The support substrate is cut so that the assembly sheets are separated from one another. A plurality of suspension boards with circuits are aligned within a rectangular support frame in each of the assembly sheets (see, e.g., JP 2007-115828 A). Finally, each of the suspension boards with circuits is separated from the assembly sheet.
In processes for manufacturing the suspension boards with circuits discussed in JP 2007-115828 A, it is determined whether each of the suspension boards with circuits is a nondefective product or a defective product in the form of the assembly sheet.
In order to determine whether each of the suspension boards with circuits is a non-defective product or a defective product, an inspector performs visual inspection, for example. In the visual inspection, if an abnormality exists in shapes of some of the plurality of suspension boards with circuits provided in the assembly sheet, the inspector can easily distinguish between the normal suspension board with a circuit and the abnormal suspension board with a circuit. Therefore, the inspector can relatively easily determine the suspension boards with circuits in which an abnormality exists as defective products.
If a common abnormality occurs in shapes of all the suspension boards with circuits provided in the assembly sheet, however, it is difficult for the inspector to determine all the suspension boards with circuits in the assembly sheet as defective products.